1. Field of the Invention
The present invention relates to a sectional door of the type commonly used as an overhead or roll-up door on vehicles such as trucks or trailers, at loading docks, or as garage doors.
2. Prior Art
It is common to use sectional roll-up type doors at the rear end openings of trucks or trailers, at vehicle docking entrances, and as garage doors. Such doors have a series of similar horizontally extending panels or slats joined together by hinge means, the ends of the panels or hinge means having rollers which run in generally C-shaped tracks with a vertical leg at the sides of the opening and a horizontal leg above the rear of the opening. Examples of such doors are shown in the following patents:
U.S. Pat. No. 4,532,973, issued Aug. 6, 1985 to DeFalco;
U.S. Pat. No. 4,567,931, issued Feb. 4, 1986 to Wentzel;
U.S. Pat. No. 4,771,816, issued Sep. 20, 1988 to Clay, Jr.;
U.S. Pat. No. 4,930,561, issued Jun. 5, 1990 to Clay;
U.S. Pat. No. 4,991,639, issued Feb. 12, 1991 to Clay, Jr.;
U.S. Pat. No. 5,419,386, issued May 30, 1995 to Magro et al. and
Can.Pat.Appln.No.2,147,199, published Oct. 19, 1996.
Hitherto, such doors, as used for trucks, have been made of various materials including plywood, often provided with aluminum or steel skins, stamped steel, and extruded thermoplastic and aluminum. In the trucking business, such doors are often damaged, for example by fork trucks, and there is frequent need to replace panels and hinges. It thus becomes important that panels, and the connecting hinges, be easily replaced. But in general laminated panels when punctuated allow moisture to enter the interior being quickly absorbed by the wood core. With the thaw/freeze cycles there is expedited de-lamination, not to mention the increased weight concerns.
Some hinge arrangements, such as that shown in the aforesaid Canadian application, have a long hinge pin or pintle which needs to be extracted sideways when replacing panels; this is often difficult due to lack of space.
The same problem would seem to occur with the design used in the Wentzel patent, where a male hinge member must be threaded into a female member to assemble the hinges and panels.
Other designs, such as that of DeFalco, have a hinge arrangement which can be taken apart only when adjacent panels are at about 90.degree. to each other. Depending on the track design, the panels will normally only be able to hinge through about 70.degree. or 50.degree. relative to each other, but the hinges can be disassembled by removing the end rollers from one hinge, and pivoting the adjacent panels to the 90.degree. orientation. However, this can only be done at the corners of the track, which is not always convenient.
A further perceived drawback of some known designs, such as that of Wentzel, is that the male hinge member or pintle is only partially surrounded by the female member, and could seemingly pull out at least if these members were made of resilient material such as plastic.
Currently, most roll-up doors in the industry have bolted hinges, which fasten the individual panels. These bolts tend to rust or oxidize, coupled with drill holes that in time tend to enlarge allowing water to leak into the panel. This creates a most unattractive exterior door appearance. The exterior bolts are not flush to the panel surface making it difficult to attach corporate logos or advertisements. On the interior surface the hinges are also not flush to the panel surface which tends to catch freight.